The printed pages have black vertical lines or streaks. How can I improve the
print quality?

Description of Solution 200000037166

Brother
strongly recommends that customers use only genuine Brother drum units and/or
toner cartridges. Each Brother laser printer is designed to work at pre-set
temperatures that are matched exactly to each of our individual toner
formulations. Each individual component is designed to work with the other
to ensure quality and reliability. Using non-Brother supplies may affect the
hardware performance, print quality, and machine reliability. The Brother
limited warranty does not apply to any problem that is caused by the use of
third party drum units, toner cartridges, or toner.

3.
This issue is usually resolved by cleaning and/or replacing the drum. Manually
clean the drum surface by following the instructions listed below:

a.
Open the front cover.

b.
Take out the drum unit and toner cartridge assembly by pulling on the handle in
the middle of the drum unit and toner cartridge assembly.

NOTE: We
recommend that you place the drum unit and toner cartridge assembly on a piece
of paper in case you accidentally spill or scatter toner.

c.
Push down the green lock lever on the left side of the drum unit and toner
cartridge assembly and then lift the toner cartridge out of the drum unit.

NOTE:
Handle the toner cartridge carefully. If toner scatters on your hands or
clothes, immediately wash it off with cold water.

d.
Inside the drum unit is a roller. Clean the roller by gently wiping the entire
surface with a lint free cloth or cotton swab lightly moistened with isopropyl
alcohol (91% strength alcohol is preferred, but 70 - 75% strength alcohol is
also acceptable). You can also use an alcohol swab, such as a medical
alcohol pad or wipe, which can be found in a first aid kit. Use the white
gear on the far left side to turn the roller and ensure you clean the entire
surface.

As a
precaution please note:Isopropyl
alcohol is flammable and should be kept away from fire or flame.

- If
physical damage, such as scratches, nicks or gashes in the surface of the drum,
is found when inspecting the drum, there is no need to continue cleaning since
it will not resolve the issue. The drum (DR720) needs to be
replaced.

e.
Before continuing further, allow the alcohol to evaporate or dry off the drum
surface.

f.
Once the drum surface is dry, clean the primary corona wire inside the drum unit
by gently sliding the green tab located at the top of the drum unit from left to
right and back several times. Be sure to return the green tab to the home
position (1).

h.
Reinstall the toner into the drum (be sure it clicks into place). If you put it
in properly, the green lock lever will lift automatically.

i.
Reinstall the drum unit and toner cartridge assembly into the machine, close the
front cover, pressing firmly on each side until the cover clicks into place.
Turn on the machine's power switch.

4.
Print 10 to 15 blank pages from the computer to further clean any remaining
debris left on the drum surface.